active scenery config file order

[Griphos]

I see that TE GB1 installs three lines into the scenery config file.  One is for orthos, one for overlays, and the third is called Orbx_A_GB_South_TrueEarth_Custom.  Is this a library file?  I'm trying to decide where to put it in the order of the config.  The installer just put the three of them in randomly, and I moved the other two to appropriate places in the list.  Don't know where this one should go.